Xanthine oxidoreductase activity correlates with vascular endothelial dysfunction in patients with type 1 diabetes

Xanthine oxidoreductase (XOR) is an enzyme regulating uric acid synthesis and generation of reactive oxygen species. Several studies suggested relationship between XOR and atherosclerotic diseases; however, few previous studies have directly examined the relationship between XOR and vascular endothelial dysfunction in patients with type 1 diabetes mellitus (T1DM). The aim of this study was to evaluate the relationship between XOR activity and vascular endothelial function in patients with T1DM. Seventy-one patients with T1DM participated in the study and underwent assessments, including plasma XOR activity and flow-mediated dilation (FMD), to measure vascular endothelial function. The natural logarithm value of XOR activity (ln-XOR) was 3.03 ± 0.99 pmol/h/mL, and FMD was 5.5% ± 2.4%. FMD was inversely and significantly correlated with ln-XOR (correlation coefficient: r = − 0.396, P